N－取代硫代磷酰胺二乙酯合成新方法的研究

以ＰＥＧ作相转移催化剂，在无机碱（Ｋ＿２ＣＯ＿３或Ｎａ＿２ＣＯ＿３）存在下，用乙基氯化物（Ｏ，Ｏ－二乙基硫代磷酰氯）与不同的胺反应，合成了六种Ｎ－取代硫代磷酰胺二乙酯，其结构经ＩＲ、ＮＭＲ和元素分析证实。     

All-atom molecular dynamic simulations and relative NMR spectra study of weak C-H...O contacts in amide-water systems

Amide-water mixtures are studied by all-atom molecular dynamics (MD) simulations and the relative temperature-dependent NMR experiment. The weak C-H...O contacts are found in the amide-water systems theoretically and experimentally. The statistical results of the average numbers of hydrogen bonds indicate that the methyl groups in amide molecules represent different capabilities in forming the weak C-H...O contacts. The statistics also imply that the C-H...O contacts are more obvious in the amide-rich region than those in the water-rich region. The temperature-dependent NMR spectra are also adopted to investigate the weak C-H...O contacts in the amide-water systems. The relative chemical shifts of the methyl groups are in good agreement with the MD simulations.     

L—半胱氨酸与铁镍锌铅离子配位反应的热力学

L—半胱氨酸(L—Cys)是蛋白质的降解产物之一,在体内除参与蛋白质的合成外,还参与毒物的解毒过程。本文用pH电位滴定法测定L—Cys同Fe~(2+)、Ni~(2+)、Zn~(2+)、Pb~(2+)形成配合物的稳定常数,以温度系数法获得配位反应的焓变,根据所得的热力学参数,对配位反应的推动力和配合物的结构进行讨论,并进一步用红外光谱和电子光谱对Pb~(2+)、Ni~(2+)两体系所得的结果予以证实。     

新型氮杂2-β萘基苯并噁唑分子设计与光物理性质的研究

为了寻找新的有效光敏材料，设计了一系列新型氮杂2-β萘基苯并恶唑分子，用改进的PPP-SCF-CI方法，对设计分子的第一激发单线态，三线态，振子强度和跃迁矩等光物理性质进行了较为详细的研究，筛选出了一些新型的具有特殊光物理特性的分子，并预测了有可能产生新型氮杂2-β萘基苯并恶唑分子类光敏感功能材料的取代基部位。     

氨基酚异构体的离子对反相液相色谱分析的研究

本文研究了离子对反相液相色谱分析氨基酚异构体的可能性、影响因素和色谱条件，发现以含４×１０－８ｍｏｌ／Ｌ四丁基碘化铵、０．１８４ｍｏｌ／Ｌ醋酸钠的甲醇水溶液（２３：７７）作为流动相，ＯＤＳ为固定相时可以实现氨基酚异构体的良好分离。     

Cloning and Expression of Rat Liver S-Adenosylmethionine Synthetase

Introduction S Adenosylmethionine(SAM)isabiologicallyac tivecompoundwidelydistributedinthebodytissues andfluids.Itisinvolvedinanumberofbiochemical reactions.Asamethylgroupdonor,itisimportantin transmethylationreactions,whichcontributestothe synthesesofsuc…     

Synthesis of gramicidin S and its analogues via an on-resin macrolactamization assisted by a predisposed conformation of the linear precursors

A simple and efficient preparation of gramicidin S and its analogues is described. It involves solid-phase peptide synthesis and on-resin macrolactamization without side chain protection, affording cyclic products in high yield and high purity. The high specificity of the cyclization reaction was shown to originate in the formation of a pre-organized conformation of the linear biosynthetic precursor of gramicidin S. This facile method will provide convenient access to the analogues of the natural product for functional optimization to counter microbial resistance.     

室温熔盐二(三氟甲基磺酸酰)亚胺锂-尿素体系的分子动力学模拟

应用分子动力学模拟了25 ℃和50 ℃时新型室温熔盐二(三氟甲基磺酸酰)亚胺锂[LiN(SO2CF3)2, LiTFSI]与尿素(摩尔比为1:3.6)体系的结构与动力学性质. 在两个温度下体系的微观结构基本相同, Li+的配位数约为5, 且都是与溶剂和阴离子中的氧原子发生配位. 对TFSI-的研究表明, 每个TFSI-只提供四个氧中的一个与Li+配位; 而且在Li+的配位层中, TFSI-具有顺、反和gauche 等不同的构象, 并且不同构象出现的几率会随着温度的改变而改变.     

IMPROVED PROPERTIES OF METALLOCENE-CATALYZED LINEAR LOW-DENSITY POLYETHYLENE/POLYPROPYLENE BLENDS DURING ULTRASONIC EXTRUSION

Metallocene-catalyzed linear low-density polyethylene/polypropylene （mLLDPE/PP） blends were prepared by ultrasonic extrusion in this work. Their extrusion processing behaviors were estimated by online measured data, such as the die pressure and flow rate. Crystallization and mechanical properties of the blends were also investigated. The results show that the addition of PP improves the processing behaviors of mLLDPE, but has little effect on its mechanical properties. On the other hand, the addition of mLLDPE improves the impact strength of PP, but has little effect on its processing behavior. The processing behaviors and mechanical properties of mLLDPE/PP blends get further improved due to the presence of ultrasonic oscillation during extrusion. Compared with PP-rich blends, the apparent viscosity drop of mLLDPE-rich blends is more sensitive to ultrasonic oscillation. The ultrasonic oscillation affects the crystal nucleation, while barely the other crystalline behaviors of the blends.